1. Technical Field of the Invention
The present invention generally relates to the telecommunications field and, in particular, to a communications network and method for directly routing calls to called mobile parties using an Internet Protocol (IP) network.
2. Description of Related Art
It is well known that using an IP network for routing a long distance call can be offered at a low price by an operator as a supplementary service commonly referred to as Voice over IP or VoIP service. The operator is able to provide the VoIP service at a low price, because there is no requirement to pay accounting fees to other operators for utilizing their networks to connect the long distance call. Currently, the VoIP service is offered mostly by operators of Public Switched Telephone (PSTN) Networks, however, there is a growing interest among operators of Public Land Mobile (PLMN) networks to provide such services to mobile subscribers.
Referring to FIG. 1, there is a flowchart illustrating the conventional steps used to complete a long distant call to a called mobile subscriber using an IP network. Beginning at step 100, a calling party using the VoIP service initiates a call directed towards a called mobile party. The calling party can be a fixed subscriber using the PSTN network or a mobile subscriber using the PLMN network.
At step 102, the IP network is used to obtain an address associated with a home mobile network of the called mobile as party. At step 104, the IP network routes the call to the home mobile network at which the called mobile party subscribes to receive telecommunications service. At step 106, a determination is made at the home mobile network as to whether the called mobile party is currently located within the home mobile network or is currently roaming within another mobile network known as a destination mobile network. If the called mobile party is located within the home mobile network, then at step 108 the call is connected between the calling party and the called mobile party using the IP network and the home mobile network.
In the event the called mobile party is currently roaming within the destination mobile network, then at step 110 the home mobile network is used to obtain routing information indicating the current location of the called mobile party. At step 112, the call is then connected between the calling party and the called mobile party by routing the call from the home mobile network through the IP network to the destination mobile network.
Unfortunately, to connect the call between the called party and the roaming called mobile party requires that the call be routed from the IP network to the home mobile network and then routed from the home mobile network to the destination mobile network through the IP network. Consequently, the long distance of such a route is problematic in that extra signaling is required between the three networks and a delay in connecting the call may be increased to an unsatisfactory level due to the involvement of the home mobile network in routing the call.
Accordingly, there is a need for a method and communications network that enables a determination at an IP network as to whether a called mobile party is currently roaming and, if so, then routes the call directly to a destination mobile network occupied by the called mobile party while bypassing a home mobile network. This and other needs are satisfied by the communications network and method of the present invention.
The present invention is a method and communications network that directly routes a call from a calling party to a called mobile party using an IP network. More specifically, the method includes the step of determining at the IP network whether the called mobile party is currently roaming outside a home mobile network. In response to an affirmative determination, an address of a destination mobile network currently occupied by the called mobile party is obtained at the IP network, and the call between the calling party and the called mobile party is connected using the IP network and the destination mobile network while bypassing the home mobile network. In response to a negative determination, an address of the home mobile network is obtained at the IP network, and the call between the calling party and the called mobile party is connected using the IP network and the home mobile network.
In accordance with the present invention, there is provided a method and communications network that enables the IP network to function as an IP backbone for directly routing international and long distance calls to called mobile parties.
Also in accordance with the present invention, there is provided a method and communications network that updates the IP network with current routing information indicating the current location of a called mobile party that is roaming outside of their home mobile network.